Majority of life diversity yet to be discovered
Copyright 2001, Environmental News Network
September 07, 2001
By David Suzuki
One realizes just how little we know about life on Earth when the largest animals currently walking the face of the planet are found to actually be two quite distinct species.
For more than 100 years it had been assumed that there were two species of elephants: Asian and African. But recently, using DNA analyses, researchers found that African elephants are really comprised of two genetically separate groups, as distinct as lions and tigers.
On one hand there are African forest elephants, and on the other, African savanna elephants. The two actually look quite different, but it was generally believed that one might, at most, be a subspecies of the other. However, new evidence indicates that their DNA patterns are genetically isolated.
African elephants are massive, charismatic mammals that immediately intrigue people. They have been studied extensively and figure prominently in human culture and mythology. Yet here they are, two separate species, and we never knew.
If we know so little about Earth's giants like elephants, how much could we possibly know about the myriad of tiny creatures that help create the backbone of life on Earth: the insects and arachnids, fungi and bacteria?
Our catalogue of Earth's diversity seems impressive, boasting some 250,000 described plant species, 750,000 insect species and 280,000 other animals. But incredibly, we have yet to discover most of the Earth's species. Scientists have documented maybe 10 or 20 percent of living things, and new species are discovered all the time.
Last year, for example, researchers in the Brazilian Amazon found two species of brightly colored monkeys that had never before been recorded. Earlier this year, a new owl was discovered in Sri Lanka. And an unusual form of antelope, the saola, was found in Vietnam a few years ago.
Even more is yet to be discovered underwater. Anyone who has ever snorkeled over a healthy coral reef knows what it's like when you first put your head in the water. It's shocking. The sheer numbers of fish and the amazing diversity is almost frightening at first.
But even areas that appear relatively empty can house a surprising diversity of life. A study of the muddy sea floor off North America's East Coast, for example, found nearly 800 species in a 25-square-meter area.
Sea-dwelling creatures may be some of the most fascinating on the planet. Creatures living around hydrothermal vents, for example, must endure incredible temperatures and toxic gases, yet many species have been found thriving in these harsh environments.
On average, a new species of large mammal is found every three years, and a new large vertebrate is found in the open ocean every five years. But the vast majority of discoveries are of much smaller creatures, such as fungi and insects. And while scientists are hard at work cataloguing some 300 new species every day, we know the life-cycle details of a tiny fraction of those we have identified.
In his book, Something New Under the Sun, historian J. R. McNeill says that humanity's most important change of the 20th century wasn't sending a person to the moon, splitting the atom, the rise and fall of communism, the advent of human rights or the feminist movement, or either of the World Wars. McNeill says that, from a historical perspective, the single biggest change of the last century was the change humans have made to the environment.
It's hard to disagree. We've fundamentally altered not only the surface of the Earth with agriculture, cities, roads, and dams, but we've actually altered the hydrologic cycle, the carbon cycle, and the climate. Because of continued population pressures, deforestation, pollution, and other problems, thousands of species become extinct every year.
That's why it's so uplifting to find a new species. They remind us of how much we still have to learn about the planet's biodiversity and about how it all works to keep the Earth liveable. Maintaining that diversity is one of the greatest challenges of the 21st century.